Grinding machine



July 2, 1935. c. HERFURTH GRINDING MACHINE FiledMay 27, 1952 6 Sheets-Sheet 1 July 2, 1935.

6 Sheets-Sheet 2 Filed May 27, 1932 July 2, 1935. c. HERFURTH 2,006,554

GRINDING MACHINE Filed May 27, 1932 6 Sheets-Sheet 3 4 019% j] a 5 jz j 4; L 0'2 3mm 0? L1 M 674944; Maw

y 1935- c. HERFURTH 2,006,554

GRINDING MACHINE Filed May 27, 1952 6 Sheets-Sheet 4 If]? i I W H A I 7 w July 2, 19 35. C HERF'URTH 2,006,554

GRINDING MACHINE Filed May 2'7, '1932 6 Sheets-Sheet 5 July 2,1935. c. HERFURTH 2,006,554

GRINDING MACHINE Filed May 27, 1952 e Sheets-Sheet s fl W M W M, w w lwlvl g x w Q bN Patented July 2, 1935 I UNITED STATES PATENT OFFICE GRINDING MACHINE Charles Herfurth, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application May 27, 1932, Serial No. 613,901

11 Claims. (Cl. 51-105) This invention relates to improvements in maactuating mechanism taken on line 8--8 of Figchine tools and especially to improvements in ure 7. compensating mechanism for maintaining proper Figure 9 is a sectional view through the head relation between the tool and work. r adjusting mechanism taken on line 99 of Fig- An object of the invention is the provision of ure 3. 5

improved control means associated with the tool- Figure 10 is a elevational view of a valve and feed mechanism to insure successive work pieces its control for actuating the piston shown n being reduced to the same size. Figure Another object of the invention is the provision Figu 11 is a r nsv r sec i n l vi w hrou 10 of a grinding machine including a grinding wheel a manually operated valve controlling the actua- 10 and truing mechanism therefor and improved tion of the truing mechanism transversely of the means for compensating or varying the relationgri di g W ship between the grinding wheel and the work in Figure 12 is a diagrammatic Vi w illu tin accordance with normal reductions in diameter the electrical and hy a Circuits involved in 15 of the grinding wheel due to normal break down this invention. 15 and truing thereof. Throughout the several views of the drawings A further obje t of th i ti i th prosimilar reference characters are employed to vision of improved means for maintaining the dedenote the Same similar partssired relationship between the grinding wheel and It has been P D d to produce machine a work piece whereby the work pieces are reduced c pr ing a plu f l 0 in d, 00 units 20 to the same size within prescribed narrow limits which are automatically and independently actuof tolerance. ated for independent operation on spaced por- Other objects and advantages of the present tions of a given work piece. These self-contained invention should be readily apparent by reference units are relatively massive and cover a considers to the following specification considered in conable area so that certain of the controls, particujunction with the accompanying drawings, formlarly the truing mechanism, are remote from the ing a part thereof, and it is to be understood that operator rendering it difiicult to properly actuate any modifications maybe made in the exact strucsaid mechanism. Furthermore, the operation of tural details there shown and described within the truing mechanism in the past has resulted in the scope of the appended claims without exceedthe work being produced outside of the limits 30 ing or departing from the spirit of the invention. of tolerance prescribed for the work, so that the In the drawings: operator must bring his machine within size by Figure 1 is a front elevation of a grinding mathe cut and try method, which consumed a conchine embodyingthe improvements of this insiderable portion of time. By this invention, the

vention. machine after being once brought into adjust- 35 Figure 2 is a top plan view of the machine ment for producing work pieces within the preshown in Figure 1. scribed tolerance limits is at all times automati- Figure 3 is a sectional view through a selfcally maintained in proper adjustment. While contained wheel head associated with the mathe invention is illustrated in the drawings and 40 Chine and as s particularly m n 3-3 n will be particularly described as respects a multi- 40 Figure 2 but with the swivel bracket member 81 ple production machine, it is to be understood swung outward into a p i h h the that the invention has equal application to single hand wheel 92 overlies the drive motor 41. it hine Figure 4 is a sectional view taken on line 4-4 The machine illustrated in t drawings of Figure prises a relatively low rectangular bed or bed 45 Figure 5 is a sectional view taken on line 5-5 plate l5 having rising therefrom. centrally there- .of Figure 3. of a rib l6 providing. on its upper surface a dove- Figure 6 is an elevational view of a cam assotailed guide ll. Associated with the guide I! ciated with the self-contained wheel head for at one end is the self-contained head stock I8 to controlling the yc gh which the wheel and at the other end the self-contained tail stock head passes. l9, respectively providing suitable work support- Figure '1 is a sectional view through the truing ing centers for the work, which is mounted bemechanism taken substantially on line 'l'-l of tween them. Arranged on the bed IS on both Figure 2. sides of the central rib l6 are the self-contained Figure 8 is asectional view through the truing tool heads, 20, 2|, 22 and. 23, which are substan- 55 .stocks to the-discharge chute 29.

tially identical in construction wherefor the single head will be described in detail later. The bed l5, see Figure 1, has rising from the opposite ends thereof posts or columns 24 and 25 supporting at their upper ends a rail 26, which overlies the rib l6. Secured to the rail 26 and depending therefrom is a'frame 21 forming a magazine 28 for unfinished work pieces and supporting a discharge chute 29 for the reception of finished work pieces. Depending from the rail 26 adjacent the magazine and discharge chute is a slide or guide 30 for a work support or carrier 3| adapted to receive unfinished work pieces from the magazine 28 and position same between the supporting centers of the head and tail stocks. The carrier 3| is further adapted to carry finished work pieces from between the head and tail The carrier 3| is hydraulically actuated for the control of which the rail 26 supports the proper valve controlling members 32. The foregoing form no particular part of the invention of this application except in combination, as will later appear.

Each of the wheelheads consists of a base 33 adapted to be secured in any desirable position on the bed I having formed on its upper surface a dove-tailed guide 34 received in a similarly shaped guideway 35 formed in a slide 36. The slide 36 is provided at its forward end with trunnion bearings 31 in which is secured a trunnion or pivot shaft 38 having its opposite ends projecting from the trunnion bearings 31. The projecting ends of the trunnion 38 are loosely received in arms or lugs 39 and 40 depending from the wheel carriage 4|.

The wheel carriage 4| supports suitable bearings or journals 42 in which is rotatably journaled a spindle 43 to the forward end of which is secured the grinding wheel in any suitable or desirable manner. The rear end of the spindle 43 is provided with a chain sprocket or gear 44 about which extends the driving chain 45 which is in turn journaled about a sprocket secured to the end of motor shaft 46. The motor shaft 46 is associated with a prime mover or an electrical motor 41 mounted upon the upper surface of the carriage 4| provided for that purpose.

The carriage 4| is adapted to be oscillated about the axis of the trunnion 38 toward and from the work to effect a reduction in the size of the work to the desired size, which is within certain definite tolerances, variably specified as several ten-thousandths of an inch or one or two thousandths of an inch. In order to oscillate the carriage 4|, it has secured to its under surface a bracket 48 having rotatably journaledtherein anti-friction roller 49 contacting with the surface 50 of a cam 5| securedto the shaft 52 and rotatably journaled in the carriage 36. The cam 5| is shown in Figure 6 and comprises a low point 53 which when in contact with the 55 to the point 56 the periphery of the cam rises gradually to effect the actual stock removal or grinding on the work from which point to the point 51 the periphery is concentric allowing a dwell in the relative movement of the work and grinding wheel and permitting the sparking out of the grinding wheel. The periphery of the cam sharply falls away or declines from the high point 51 to the low point 53 for rapidly retracting the grinding wheel from the work after it has been'reduced to the desired size and finish. From this it will be seen that the grinding wheel rapidly approaches the work, reduces same to size, dwells to properly clean up and finish the work, and then rapidly withdraws from the work.

In order to rotate the cam 5| the slide 36 supports beneath the carriage 4| a prime mover or electric motor 58 having secured to its shaft a pinion 59 meshing with a gear 60 on one end of a shaft 6| journaled in suitable bearings provided by the slide 36 and the change gear housing 62. The shaft 6| carries, in addition, a gear 63 which drives through a suitable transmission or gear train to the change gear 64 on one end of a shaft 65 and driving through gears 66 to a worm shaft 61. The worm shaft 61 is journaled in bearings provided by the slide 36 and change gear housing 62 and has integral therewith a worm 68 meshing with a worm wheel 69 on the cam shaft 52. From this it will be seen that the grinding wheel may be oscillated through the cycle above described at different speeds by changing the gears 64 and that the grinding wheel is actuated toward and from the work.

In order to vary the position of the grinding wheel relative to the base plate 33 the said base plate is provided at its forward end with an upstanding lug 18 having a threaded perforation therein receiving the threaded end of a screw 1| rotatably journaled in a lug 12 depending from the lower surface of the slide 36. The rear end of the screw is reduced as at 13 and is journaled in a socket 14 formed in the slide 36. Between the lug 12 and socket 14 the carriage is relieved to provide a passageway in which is disposed a spiral gear 15 secured to the reduced end 13 of the screw. Meshing with the spiral gear 15 is a complementary spiral gear or worm secured to or formed integral with a vertically extending shaft 16 which is rotatably mounted in a sleeve 11 carried by the slide 36. The sleeve 11 is enclosed within a guard sleeve 18 which is also carried by the slide 36 and passes upwardly through an enlarged opening 19 formed in the upper surface of the carriage 4|. struction the carriage 4| may be oscillated relative to the slide 36 without interference from the guard sleeve 18 or the parts enclosed thereby.

In order to prevent foreign materials from entering within the carriage 4|, the sleeve 18 carries at a point above the opening 19 a cap or cover 80 normally sealing the said opening 19.

The vertical shaft 16 extending through the sleeve 11 is journeled on anti-friction bearings 8| mounted on the upper surface of the sleeve 11 and the bearing 8| contacts on its other surface with .a collar 82. At the upper end of the shaft 16 beyond the collar 82 it is provided with a reduced portion 83 to which is keyed or otherwise secured a worm wheel 84. The worm wheel 84 is secured to the reduced portion 83 of the shaft by means of a nut 85 threaded to the extreme end of said shaft for clamping the worm wheel between itself and the shoulder at the end of the reduced portion 83. The worm wheel 84 has meshing with it a worm which is secured to or formed integral with a shaft 86 journaled at opposite ends in a swivel housing 81. The swivel housing 81 has at its one end a split collar 88 which encircles the upper reduced end of the guard sleeve 18. The collar 88 is concentric with By this conthe axis of the guard sleeve 18 and the vertical shaft 16 so that by loosening the clamp the swivel housing 81 may be oscillated about the axis of the shaft 16 to dispose the outer end of the shaft 86 at any point as respects the bed of the machine. This is illustrated in Figure 2 where it will be seen that the ends of the said shafts terminate-adjacent the portion 89 of the bed plate I5 intermediate the wheel heads 22 and 23 which constitutes the operator's station.

The outer end of the swivel housing 81 terminates in a collar 90 in which is journaled the end of the shaft 86 and to which is secured the control mechanism indicated generally by the vnumeral 9|. The shaft '86 is reduced in order to pass through the unit 9| and has secured to it exteriorly of said unit a hand wheel 92 whereby the shaft 86 is rotated for rotating the shaft 16 and through the spiral gear 15 the screw 1I, thereby adjusting the slide 36 and parts carried thereby relative to the base 33.

The control unit 9| consists of a ratchet '93, see Figures 3 and 9, keyed or otherwise secured to the reduced end 94 of the shaft 96. This ratchet is enclosed within a cavity 95 formed in ahousing 96 that forms the control unit 9I. Secured to the housing and interiorly thereof is a plate 91 having projecting therefrom a bearing sleeve 99 which encircles the reduced end 94 of the shaft. Loosely journaled on thecollar or sleeve 98 is a segmental gear 99 having the teeth I thereof meshing with a rack IOI formed on or secured to the upper surface of a double acting piston I02. The piston I02 is contained within a cylinder I03 formed in the housing 96. The cylinder I03 is closed at opposite ends by heads I04 and I05 I extending respectively from which are the screws I06 and I 01 acting as stops or limits for the travel of the piston at each end of its movement. Pivoted as at I08 to the segmental gear 99 is a pawl I09 having its nose IIO adapted to engage with the teeth of the ratchet 93. The other end of the pawl I09 engages with a spring III extending from a spring carrier I I2 projecting from the segmental gear 99. Passing through the upper wall of the housing 96 into the chamber 95 is a thumb or look out screw II3 adapted to engage with the tail of the pawl I09 for disengaging the nose th ereof from the ratchet teeth 93. The lock screw I I3 has associated with it a lock nut I I4 for looking it in its adjusted positions.

When the piston I02 is at the left hand limit of its movement, as seen in Figure 9, the ,lock out screw II3 engages with the end of the pawl I09 for holding the same disengaged from the ratchet 93 at which time the slide and carriagemay be actuated through the hand wheel 92. It is the purpose of the ratchet and pawl mechanism, as willlater appear, to automatically and periodically actuate same for periodically advancing the parts controlled thereby to maintain the work at all times within certain prescribed limits of tolerance. tuated relative to the cylinder by means of hydraulic pressure, which will be later described.

Each of thegrinding wheels associated with the heads 20 to 23,- inclusive, is adapted to be trued by mechanism individual to the respective heads but of similar construction wherefor it is believed that a description of one of them will suffice for all.

Accordingly, as seen in Figures 7 and 8, the wheel carriage M has secured to it the bracket II5 to which is secured a block II6 by means of bolts or the like H1. The block II6 has formed The piston I02 is adapted to be ac-,

therein a cylinder H8 in which is mounted a piston, H9. The cylinder is closed at opposite ends by the heads I20 and I 2| which limit the extent of travel of the piston relative to the cylinder. Secured to the piston and projecting therefrom is a piston rod I22 which passes through the head I 2| and has secured to its outer end the depending lug I23 of a slide I24. The slide I24 is provided with a dove-tailed guideway tongue I26 formed on the upper surface of the block H6. The piston H9 is adapted to be actuated by hydraulic pressure introducedalternately to the opposite ends of the cylinder.

The slide I24 has formed integral therewith or secured thereto a sleeve bearing or barrel I21 in which is disposed a bar I28 adapted to be axially shifted relative thereto. The bar I28 has secured to its upper end as by cap screws I29 a nut I30 in threaded engagement with a screw I3I. The inner end of the bar I29 has secured therein a diamond holder I32 for the diamond I33 which is adapted to operate upon the periphery of the grinding wheel.

The barrel I21 terminates in an enlarged head I34 forming interiorly thereof a chamber I35. Secured to the base of the chamber I35 interiorly thereof is a plate member I36 having projecting from it a bearing boss I31. Contacting with the under surface of the plate I36 is a shoulder I38 of the screw I3I which limits the axial movement of said screw in one direction. Keyed or otherwise secured to the reduced portion I39 of the screw and abutting the end of the plate bearing I31 is a ratchet I40 being secured against movement relative to the'screw by means of a nut MI. The nut I4I co-operates with the shoulder I38 to secure the screw I31 against axial movement in either direction relative to the barrel I21. Secured to the head I34 of the barrel I21 is a cover plate I42 through which the screw I3I projects to receive the hand wheel I43 for manual rotation of the screw and initial setting of the parts.

Loosely journaled on the plate bearing I31 is a segmental gear I44 having its teeth I45 in mesh with a rack plunger I46 axially shiftable relative to a cylindrical housing I 41 formed integral with the barrel head I34 at a point below the segmental gear I 44. A pin and slot connection I48 limits the axial adjustment of the rack plunger I46 relative to its housing I 41. Pivoted as at I49 to the segmental gear I44 for movement therewith is a pawl I50 having a nose I 5| adapted to engage the teeth of the ratchet I40. Abutting the end of the pawl I50 is a spring I52 carried by the spring carrier I53 projecting from the side of the segmental gear I44. Extending through the barrel head I34 is a lock out screw I54 adapted to engage with the tail of the pawl I50 for raising the nose I5I out of engagement with the ratchet teeth when the segmental gear- I44 is at one end of its rotary movement. With the parts in this position, the screw I3I may be rotated manually by the hand wheel I43.

As was mentioned above and as will be seen from Figure 2, in order to actuate the diamond relatively to the wheel it was necessary, in the past, for the operator to leave his station 89 and I25 receiving a correspondingly shaped valves, each identical in construction and respectively operated by hand levers I55, I56, I51 and I58. One of the valves is shown in detail in Figure II and consists of a body portion I59 in which is mounted a rotary valve plug I60 having grooves cut therethrough at points diametrically opposed to one another to form the passages I6I and I62. The valve handle is secured to the plug I60 for oscillating same for atone time connecting the port I63 formed in one side of the body I59 with the port I64 as by way of the passage I6I and at the same time connecting the port I65 with the port I66 as by way of the passage I62. Oscillation of the valve plug I60 in a counterclockwise direction will connect the port I63 with the port I66 by way of the passage I6I YGhiIB the passage I62 connects the ports I64 and By reference to Figure 12, it will be noted that the port I63 is connected by a conduit or pipe I61 with the discharge side of a pump I68 adapted to draw an hydraulic medium such as oil from a tank or sump I69 through a suction pipe I10. The port I64 is connected by means of the pipe or conduit I1I with one end of the truing tool traversing cylinder II 8. The other end of this cylinder is connected by means of the pipe'or conduit I12 with the-port I66 while the remaining port I65 is connected by a discharge pipe or conduit I13 with the tank or sump I69. As shown in Figure 12, the valve plug I60 is in the same position as that illustrated in Figure 11, thereby connecting pipes I61 and "I for directing the presssure against the right hand end of the piston H9 and actuating the slide I24 to the right as seen in Figure 12. This exhausts the hydraulic medium ahead of the piston I I9 through the pipes I12 and I13 to the tank I69.

The block II6 has secured to its right hand end, as seen in Figure 8, a bracket I14 which has extending upwardly therefrom an arm I15 carrying an adjustable screw I16 for engagement with the end of the rack plunger I46 as the slide I24 reaches its right hand end of travel, as seen in Figure 8. The arm I15 is further provided with a momentary switch I11 having projecting therefrom the switch actuator I18 mounted in the path of travel of an adjustable abutment I19 conveniently taking the form of a screw or bolt threaded into a lug I depending from the lower surface of the plunger housing I41. The block I I6 has secured to its side portion and projecting upwardly therefrom an arm I 8| in which is mounted an adjustable abutment screw I82 for engagement with the other end of the rack plunger I46. The plunger I46 is utilized for setting the segmental gear I44 relative to the ratchet I40 preparatory to the next .infeed of the diamond carrier I32 which is accomplished at the other end of the stroke of the slide I24 namely by the abutment I82.

As was noted above, in the past after the wheels had been trued the relation of their operative faces as respects the axis of the work was destroyed so that it was necessary for the operator to again reset the parts by the cut and try method. This again consumed a considerable portion of valuable grinding time during the hand measurement of the parts. Since the greatest variance between the wheel axis and the work axis takes place at the time that the wheels are trued, there has been provided a mechanism compensating for the amount of stock or material removed from the wheel after each truing thereof. For this reason, the infeed shaft 86 is provided with the mechanism 9I actuated by the piston I02. As shown in Figure 12, the cylinder I03 containing the piston I02 has its left hand end connected by means of the pipe or conduit I83 with a port I84, see Figure 10, formed in a valve casing I85 mounted on the carriage 4| of each head. The valve casing I85 encloses a r0- tary plug type valve I86 having extending therethrough three passages, I81, I88 and I89. Passages I81 and I89 are formed by providing slots at diametrically opposite points in the valve plug, while the passage I88 is formed through same and between the passages I81 and I89. As

shown structurally in Figure 10, and diagrammatically in Figure 12, the passage I81 is connecting the port I84 with a port I90 which has extending from it branch discharge or exhaust conduit I9I. The other end of the cylinder I03 has ne end of a pipe I92 connected thereto which pipe terminates at port I93 in the valve casing I85 and is connected by means of the central passageway with a port I94 also formed in the valve casing. The port I94 is connected by means of a pipe or conduit I95 with the pressure line I61 for conveying pressure ,to the valve casing I85. The casing I85'is provided with an additional port I96 connected by the pipe or conduit I91 with the pipe or conduit I9I which is in turn connected to the return or exhaust conduit I13. Oscillation of the valve plug I86 in a counterclockwise direction, as seen in Figures 10 and 12, will connect the central passage I88 with the port I84 and thereby direct the medium to the right hand end of the cylinder I03 instead of to the left hand end thereof as is now illustrated in Figure 12. At this time the port I93 would be connected with the port I96 for directing the exhaust medium through the line I91 instead of the line I9I as at present shown in Figure 12.

The valve plug I86 has secured to it an arm I98 in which is formed an elongated perforation I99 receiving a pin 200 extending from the upper end of link 20I. The other end of the link ZOI is pivoted at 202 to the core 203 of a solenoid 204. The solenoid 204 is adapted to be electrically energized for shifting the valve I86 at the time the momentary switch I11 is closed.

As shown in Figure 12, one terminal of the switch I11 is connected by a Wire 205 to the main positive lead 206, while the other terminal is connected by a wire 201 to a time relay switch 208 and through a wire 209 with the main negative lead 2 I0. From this it will be seen that closing of the switch I11 energizes the time .relay 208 for closing the switch 2 to which is connected one end of the wire 209. The other terminal of the switch 2II is connected by a wire 2I2 with one end of the solenoid 204. The other side of this solenoid is connected by means of a wire 2I3 with the positive lead 206.

To retract the solenoid core 203 after the current has been cut off therefrom, there is provided a. spring 2I4 having one end connected to the pivot pin 20,0 of the link 20I, while the other end is connected at 2I5 to a fixed part of the machine.

The operation of the device is as follows: A supply of work pieces is placed in the magazine 28 being normally held from discharge therefrom until the carrier 3I is in position to receive them. The carrier is then elevated by actuation of the valve control unit 32 to a position to receive the work whereupon it is lowered to position the work in alignment with the head and tail stocks, which support and rotate-same.

'I'he infeed motors 58 are then started for rotating the cam which feeds the grinding cam 5|. reaches its high point 51 the Work will be reduced to the desired size, which will be near the low limit of tolerance. FTmS adjustment of the carriage took place by means of the hand wheel 92 rotating the shaft 85 through the worm and worm wheel 84 and shaft 16 for rotating the adjusting screw-1|.

At the conclusion of the grinding operation the valve 32 is again actuated for elevating the work to the discharge chute 29 which receives said finished workpiece whereupon a new unfinished work piece is released from the magazine 28 and again lowered to position for grinding. This operation continues, the workman checking the sizes of the several portions of the work previously ground during the grinding of the work piece now in the machine. If it is found that one of the diameters is nearing the upper limit of the tolerance size, he selects the valve handle I55, I56, I51 or I58 controlling the dressing 'or truing mechanism for the desired wheel head 20, 2|, 22 or 23, which is not reducing its work piece to the desired size. This operation of the valve handle, of course, takes place while the wheels are in a retracted position and with the work carrier elevated. The operation of the desired handle shifts the valve plug I60 from the position shown in dotted lines in Figure 12 to the position shown in full lines therein. This connects the hydraulic medium with the left hand side of the piston III! for actuating the slide I24 to the right causing the diamond I33 to traverse past the wheel. In the event the wheel had worn below the point at which the diamond would engage to remove or trim its operative face, nothing would happen until the truing slide reaches its right hand limit of movement. At this time, the rack plunger I46 engages with the stop I16 which, as noted above, resets the segmental gear I44 for the next infeed movement of the diamond. At the same time, the bumper I19 carried by the truing slide engages the'switch actuator I18 for closing the electrical switch I11. This completes the electrical circuit including wires 205, 201, time relay 208 and wire 209 for closing the switch 2|I. The closing of the switch 2 completes the electrical circuit through wires 209 and 2I2, solenoid 204 and wire 2|3 for energizing said solenoid 204 and actuating the core 203 which will oscillate the valve I86 in a counterclockwise direction. The movement of the valve by the solenoid 204 connects the hydraulic medium with the left hand end of the piston I02, as

seen in Figures 12 and 9, for actuating the piston .is advanced toward the work an amount to compensate for any material removed therefrom. As is well known, a grinding wheel during use is subjected to wear and if this wear is of a greater amount than the stock removed in one pass of the diamond relative thereto, the wheel will be fed toward the work that amount. If the grinding wheel has a sufficiently true face that it is not necessary to trim same, the grinding continues without further adjustment of the parts. however, the wheel face needs truing, the valve on the rail 26 is again actuated for again passing the diamond across the wheel. As it reaches its other end of movement, it will again close the switch I11 for completing the electriealscircuits above described.

After the diamond has traversed the wheel in one direction the manual control valve is reversely actuated for withdrawing the diamond to its other end of travel. As it nears said end of travel it is engaged by the stop screw I82 which shiftsthe rack plunger I41 in a direction opposite to thatin which it was shifted by the screw I16 thereby feeding the diamond toward the grinding wheel preparatory to its next traverse relative to the wheel. The reverse movement of the slide I24 also releases the switch actuator I 18 so that the spring 2" associated therewith breaks the electrical circuit to the time relay 208 allowing it to de-energize and break the circuit to the solenoid 204. Upon de-energization of the solenoid, 204, the spring 2 I4 which was expanded upon movement of the core 203 reversely shifts the valve 86 to the position'shown in Figure 12 thereby retracting the piston I02 preparatory to the next actuation of the diamond relative to the wheel.

Through the adjustment of screws I I3 and I 54, associated respectively with pawls I09 and I50, the amount of rotation of the ratchets 93 and I40 per oscillation respectively of the segmental ,gears 99 and I44 may be varied and held equal. In other words, the oscillation of the segmental gears 99 and I44 is through equal arcs and the rotation or actuation of the ratchets must also be equal so the grinding wheel is fed toward the work'an amount equal to the reduction of the wheel as determined by the infeed set of the diamond as it passes thereover. This takes place even though the diamond does not actually remove any material from the wheel.

From the foregoing it will be noted thatthere has been provided a mechanism for maintaining an accurate set up of the wheel and work for producing successive work pieces to the same size within very close limits of tolerance.

What is claimed is:

1. In a mechanism of the class described the. combination of a grinding wheel, a work support adjacent the grinding wheel, hydraulically actuable means for incremently feeding the wheel toward the work support, means for truing the active face of the wheel, means for actuating the truing tool toward the axis of the wheel, and

means operable by the truing mechanism for operating the grinding wheel feeding means to ad- Vance the grinding wheel toward the work an amount equal to the feeding of the truing tool toward the wheel.

2. In a grinding machine for producing work pieces within definite limits of tolerance the combination of a bed, a grinding wheel mounted thereon for movement relative thereto, a work support on the bed in the line of movement of the grinding wheel, a truing tool mounted on the bed for movement transversely of the grinding wheel, hydraulic means for actuating the truing tool, means-for incremently feeding the wheel relative to the bed, and means operable by the truing tool for energizing the incremental feeding movement.

3. In a grinding machine for producing work pieces within definite limits of tolerance the combination of a bed, a grinding wheel mounted thereon for movement relative thereto, a work support on the bed in the line of movement of the grinding wheel, a truing tool mounted on the bed for movement transversely of the grinding wheel, hydraulic means for actuating the truing tool, means for incremently feeding the wheel relative to the bed, means operable by the truing tool for energizing the incremental feeding movement, and means for feeding the truing tool toward the wheel at one end of the transverse movement of the truing tool.

4. In a machine tool organization of the class' described the combination of a bed, a grinding wheel mounted thereon, a work support carried by the bed, means for feeding the grinding wheel and work support one toward the other, a truing mechanism carried by the bed and including a truing tool for truing the active face of the grinding wheel, means for traversing the truing mechanism relative to the face of the grinding wheel, and electro-hydraulic means energizable by the truing mechanism at one end of its movement relative to the grinding wheel for operating the feeding means.

5. In a machine tool organization of the class described the combination of a bed, a grinding wheel mounted thereon, a work support carried by the bed, means for feeding the grinding wheel and work support one toward the other, a truing mechanism carried by the bed and including a truing tool for truing the active face of the grinding wheel, means for traversing the truing mechanism relative to the face of the grinding wheel, electro-hydraulic means energizable by the truing mechanism at one end of its movement relative to the grinding wheel for operating the feeding means, means at the other end of the movement of the truing mechanism for feeding the tool toward the wheel a predetermined amount, and means for adjusting the feed of the truing tool toward the wheel and the relative feed of the wheel and work support whereby equal incremental feeds of the truing tool and work support and grinding wheel are obtained.

6. In a grinding machine for grinding work pieces within prescribed limits of tolerance the combination of a bed, a work support mounted thereon, a grinding wheel carried by the bed, means for effecting an incremental feed of the work support and grinding wheel one toward the other, a truing mechanism including a truing tool actuable toward and transversely to the operative face of the grinding wheel, means operable by the transverse movement of the mechanism for actuating the truing tool toward the wheel, and means operable by the truing mechanism for actuating the wheel and work support relative to one another an amount equal to the feed of the tool toward the wheel.

7. In a grinding machine for grinding work pieces within prescribed limits of tolerance the combination of a bed, a work support mounted thereon, a grinding wheel carried by the bed, means for effecting an incremental feed of the work support and grinding wheel one toward the other, a truing mechanism including a truing tool actuable toward and transversely to the operative face of the grinding wheel, means operableby the transverse movement of the mechanism for actuating the tool toward the wheel, and means operable by the truing mechanism for actuating the wheel and work support relative to one another an amount equal to the feed of the tool toward the wheel, said feeding means each comprising a screw, a rack movable relative to the screw, and a coupling between the rack and screw operable by the rack when moved in one direction for effecting the feeding.

8. In a grinding machine for grinding work pieces within prescribed limits of tolerance the combination of a bed, a work support mounted thereon, a grinding wheel carried by the bed, means for effecting an incremental feed of the work support and grinding wheel one toward the other, a truing mechanism including a truing tool actuable toward and transversely to the operative face of the grinding wheel, means operable by the transverse movement of the mechanism for actuating the tool toward the wheel, and means operable by the truing mechanism for actuating the wheel and work support relative to one another an amount equal to the feed of the tool toward thewheel, said feeding means each comprising a screw, a rack movable relative to the screw, a coupling between the rack and screw operable by the rack when moved in one direction for effecting the feeding, and means for resetting the rack.

9. In a mechanism of the class described the combination of a'bed, a work support and tool support mounted on the bed for movement one toward and from the other, a feeding mechanism for effecting an intermittent incremental feed thereof, a truing mechanism operable toward and transversely of the grinding wheel and including a truing tool for operation on the wheel, and hydraulically controlled means operable in sequential order for first feeding the truing tool toward and transversely of the grinding wheel and then feeding the grinding wheel and work support relative to one another.

10. In a grinding machine the combination of a bed, a work support and a grinding wheel carried by the bed, feeding means for feeding the grinding wheel and work support one relative to the other a predetermined incremental amount, means transversely shiftable relative to the grinding wheel for truing same, means for feeding the truing means toward the grinding wheel a predetermined incremental amount for each transverse shifting thereof, means for controlling the shifting of the truing mechanism relative to the grinding wheel, means for controlling the wheel and work support feeding means, and means operable by the truing means at the conclusion of its transversing movement for energizing the wheel and work support feed controlling means.

11. In a grinding machine the combination of a bed, a work support and a grinding wheel carried by the bed, feeding means for feeding the grinding wheel and work support relative to one another a predetermined incremental amount,- means transversely shiftable relative to the grinding wheel for truing same, means for feeding the truing means toward the grinding Wheel a predetermined incremental amount for each transverse shifting thereof, hydraulic means for transversely actuating the truing means relative to the grinding wheel, a valve controlling the operation of the hydraulic means, electro-hydraulic means controlling the feeding means of the wheel and work support, means operable by the truing means for energizing the electro-hydraulic feed control means, and a manually actuable member for the hydraulic valve.

CHARLES HERFURTH. 

